The answer is tetracyclines!!Major takeaways:-• Black hairy tongue is a benign condition characterized by hypertrophy and elongation of filiform papillae on the surface of the tongue, with brownish-black discoloration. • The condition can be associated with multiple factors, including poor oral hygiene, the use of tobacco or irritating mouthwashes, and the receipt of antibiotic agents, particularly tetracyclines. • This patient was prescribed oral minocycline, which was discontinued and an alternate regimen was started with resolution.Source: https://www.nejm.org/image-challenge